There's always a few NBA rookies who pose as injury risks out of college. This year, there was a bunch.

Five of the top 10 picks from the 2013 draft have either already experienced injury problems or recently given us a scare.

The length and grind of the NBA season is always overlooked, especially for incoming rookies who are used to roughly 30-35 games. These are the guys who've given us reason to worry heading into their first 82-game seasons.

Otto Porter Jr., Washington Wizards

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"I'm still not in the process of jogging or running, " Otto Porter Jr. told The Washington Post last week.

Uh-oh. Porter has been bothered by a strained hip flexor that's kept him out all of training camp, and it doesn't appear he'll be ready anytime soon. We've recently seen LaMarcus Aldridge and David Lee miss time due to hip injuries, which can linger if severe enough.

Porter also missed the majority of summer league after straining his hamstring. So far, we've got hip and hamstring issues before the first game of his NBA career. Sounds promising.

It just seems a little early to start with the strains. With a late start for a team looking to win now, don't expect Porter to make much of an impact early on.

Nerlens Noel, Philadelphia 76ers

A knee fracture in high school and an ACL tear in college are likely two major reasons five teams passed on Nerlens Noel.

Nobody wants to be the guy who drafts Greg Oden at the top.

Now entering his rookie season on the shelf, Noel's immediate role and availability are both in question. And with the 76ers fighting for lottery position in a throwaway year, who even knows if Philadelphia will risk putting him out there?

Noel last weighed in at 219 pounds, a number that would make him the lightest starting center in the league. Considering he doesn't play outside the paint, I'd say that's a significant detail. Between his slender frame and fragile knee, there's a good chance you won't hear too much this year from Noel.

Trey Burke, Utah Jazz

I'd say the index finger is a fairly important body part for a point guard. And Trey Burke is going to start his NBA career with one of his in a splint after fracturing it in preseason action.

According to Jody Genessy of the Deseret News, he's going to miss eight to 12 weeks after surgery, meaning his first month or two of the season is now in doubt. It's just brutal timing for Burke, who needed all the extra reps he could get after a disastrous showing in summer league.

Considering he broke the finger on his shooting hand, Burke might need extra time to regain some feel and touch. Unlike a foot injury, which can at least allow players to get some shots up, a broken finger could prevent Burke from doing any shooting until he's healed.

You just fear it's one of those injuries that's going to disrupt his rookie year.

C.J. McCollum, Portland Trail Blazers

C.J. McCollum's senior year at Lehigh was cut short when he broke the fifth metatarsal in his left foot. McCollum returned for predraft workouts and even looked terrific during summer league.

But just as preseason was getting underway, McCollum refractured that same bone in his foot.

Once is unlucky, but you worry that twice is a trend. Breaking the same bone twice in less than a year is a scary thing to think about, especially when that year occurs before your first NBA game.

He's now expected to miss an extended period of time following surgery, and though the Portland Trail Blazers haven't released a timetable, it's an injury that typically takes around two months to recover from.

You just have to hope that these were two isolated freak incidents and not a sign of trouble to come.

Shane Larkin, Dallas Mavericks

At 5'11", 176 pounds, Shane Larkin seemed like an injury risk even before he broke his ankle in July.

Larkin didn't even make it till summer league before going down and has yet to see any preseason action.

Despite his incredible year leading Miami to a No. 2 seed in the NCAA tournament, Larkin was the fourth point guard taken off the board at the draft. Credit that to scouts who feared Larkin's size and strength weren't built for the physical NBA game.

He's going to enter his rookie year fourth on the depth chart behind Jose Calderon, Devin Harris and Gal Mekel. I wouldn't bet on Larkin cracking the rotation as a rookie.